Citrix/Terminal Services/Remote Desktop Services

A recent article on Microsoft’s Ask the Directory Services Team blog piqued my interest. It talks about how leaked access tokens prevent logon sessions to be freed when the user logs off. This wastes system resources that can only be reclaimed by rebooting. A symptom of this happening is that RDS session IDs are not reused.

This is a description of a quick and dirty way to get SSL to work correctly in a VMware Horizon View installation in a lab environment. Do not do this in production!

It smacks of lazy reviewers looking for eye-candy. Simon Crosby, former Citrix CTO Citrix Synergy Team, I am writing to you as a guy who has presented many times at Synergy. This year alone I had three sessions, one in cooperation with my community peers Aaron Parker and Shawn Bass, the other two on my own - one in the Geek Speak track, the other in the regular Synergy breakout session track. All three sessions were a great success and have been rated highly.

What is API Hooking? API hooking is all about making others do things they never even knew they could do. More precisely: tricking other processes into doing things differently from what their developers programmed.

As far as I know there is no “official” way to set the width, height and screen position of Citrix Desktop Viewer in window mode. It can be done easily by changing a few registry values, though.

Update 2015-04-28: Citrix provides the limited release hotfix ICATS760WX64009 that fixes this issue. More information below. During the research for my session about the XenApp 7.6 logon process, to be presented at Citrix Synergy and BriForum London, I noticed that the logon to my XenApp 7.6 lab server was taking a bit long. Longer, in fact, than the combined durations of the main logon phases user profile loading, group policy processing, logon script execution and shell startup. Much longer. Also much longer than on an otherwise similar XenApp 6.5 machine.

If you install the Citrix XenDesktop 7.6 Virtual Desktop Agent (VDA) on a small Windows 7 VM, you may be in for a big surprise, and not a good one. This article documents issues I have experienced and how to work around them.

Last updated: 2017-01-21. This article still applies to the latest versions of GoToMeeting. The high disk space usage has not been solved yet. Am I running the latest version of GoToMeeting? Which is the latest version, anyway? Those trivial questions might not be easy to answer.

How do you programmatically determine if an application is running in a session accessed over a remoting protocol (i.e. ICA aka HDX or RDP)? It may be Citrix’ strategy to completely hide the fact that a session is remoted - which makes sense in many ways - but in some cases developers simply need to know in order to optimize their applications. It is surprisingly difficult to find official documentation about this. Here is what you need to know.

Switching over to a new computer is certainly fun for a geek, but getting back to a perfectly tuned configuration can be a lot of work, whether you synchronize (part of) your data to the cloud or not.

I am sure you all love XenDesktop VDAs that just won’t register. Although this is becoming less and less of a problem I had another case recently. Checking the Obvious When a XenDesktop VDA is unregistered the first thing I do is check if the VM is actually turned on. With that out of the way I turn to the application event log, looking for entries with the source Citrix Desktop Service. This usually tells you what the problem is. Not this time, however. Apparently the Citrix Desktop Service (aka WorkstationAgent) ran into some error during startup. It logged the following event with ID 1006 and stopped:

When you have a cloud-based file sharing service it makes a lot of sense to synchronize part or all of the data with your desktop computer. Citrix ShareFile offers the Sync for Windows tool for that purpose. However, once you open its configuration screen you notice that has a severe restriction: it can only synchronize to a single local folder. In many cases it would make much more sense to synchronize different cloud folders to different locations on your hard disk. When I complained to the product manager Peter Schulz about this I learned about a hidden gem: the single folder restriction is only present in the UI; the underlying sync engine is much more flexible. And the best thing is: the sync engine can be configured from PowerShell. Here is how.

This is the third article in a multi-part series about building and maintaining an inexpensive scalable platform for VDI in enterprise environments. Previously in this Series In the last article I explained that shared storage should be avoided, for two reasons: it is (very) expensive, and you, the VDI guy, are not in control. The storage guys are.

This is the second article in a multi-part series about building and maintaining an inexpensive scalable platform for VDI in enterprise environments. Previously in this Series I started this series by defining requirements. Without proper requirements, everything else is moot. Remember that we are looking at running typical enterprise desktop workloads, we are trying to centralize desktops and our primary desktop hosting technology is multi-user Windows, aka RDS/XenApp.

This is the first article in a multi-part series about building and maintaining an inexpensive scalable platform for VDI in enterprise environments. Requirements Before we can even start to think about a possible architecture, we need requirements. Only requirements enable us to make choices that benefit the customer. Without proper requirements we are not building for the real world but for some alternate reality. Please keep in mind when reading this article that the solution presented here only makes sense for you if your requirements are similar.

When you use XenDesktop the only way it makes sense you may find that Citrix has not really put much effort into making that a smooth experience. Persistent is a Second-Grade Citizen XenDesktop is really designed to be used with pooled desktops - machines that are reset to a pristine state when the user logs off. Of course, stateless desktops are much better (and, importantly, cheaper) served from XenApp. This has been the topic of many a debate which I will not repeat here. But I will state that if you give a so-called knowledge worker a personal desktop, you better make sure that desktop is persistent.

Cleanly shutting down all virtual machines on a given set of hosts is not as trivial as it might seem - especially if you want to be able to restore the original state once the planned maintenance you are doing this for is completed.

I had to troubleshoot a case where it suddenly was not possible any more to connect via ICA/HDX to freshly installed Windows 7 VDI machines. As it turned out, the root cause was a combination of Microsoft disabling legacy technologies and Citrix relying on them.

I just had a situation where I was facing an empty desktop with no way to logoff, start a program or do anything else. The only thing left to do was to log the session off from an admin session. This got me thinking: how many ways are there to create such a situation? I am writing down all the ways I know of and ask everybody to contribute. Can you come up with a way to end up with a completely empty desktop I and no one else thought of before?

Do you know the maximum number of users each of your terminal servers can host with acceptable performance? You may have found out the hard way how many are too many - but how many are just right? Farm sizing and server capacity planning are typical tasks for consultants who often have a hard time fighting the peculiarities of perfmon and logman trying to get the data they need for their calculations. It can be so much easier at no additional cost. The 60-day Enterprise Trial version of Splunk in conjunction with an evaluation license of uberAgent give all the information you need in much less time. Here is how.

When you move users from a physical PC to a VDI environment you may find that they are not too happy with their new machine’s performance - it happened to me. To quantify things I took a series of measurements comparing the old PCs we migrated away from with both VDI machines and the new PCs available to some.

When you buy a new HP server it comes with the BIOS setting HP Power Profile set to Balanced Power and Performance. That sounds good but is bad - at least for CPU performance in a VDI environment.

Even if you only have a moderately sized VDI deployment chances are high you will face the problem of getting USB smart card readers to work on the virtual desktops. Given that this is such a basic requirement it is astonishingly hard to implement correctly. To save you the pain of having to start from scratch here is my description of how to do it.

Know this problem? You try to start a XenDesktop session, Desktop Viewer opens … and closes. Then nothing. When you look at the machine in Desktop Studio you find that everything looks good: it is registered with the DDC and it is not in maintenance mode. However, you find an event with the following properties in the application event log: